Oxford County Simulcast Upgrade

AA1PL

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Feed Provider
Joined
Aug 18, 2007
Messages
21
Location
Hope Valley, RI
Well over a year ago I was reading/ hearing that OxfordCounty RCC Fire Dispatch and SO dispatch would be upgrading to simulcast , I heard that a contract was awarded to RCM but haven’t heard anything since. Does anyone have any updated information/ timeline?
 
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Joined
Nov 17, 2022
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5
Location
Maine
It appears that Oxford County RCC has switched over to a simulcast system. I am hearing Med-Care Ambulance and Rumford fire a lot clearer. Black Mountain also sounded distant when listening to them in the past. I now noticed after every transmission from ORCC, it has a few second period open squelch. Not sure how to minimize or get rid of that. Do not know the particulars of how they are doing a analog simulcast system. Hope someone on this forum has more information how this system works.
 

AA1PL

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Feed Provider
Joined
Aug 18, 2007
Messages
21
Location
Hope Valley, RI
I'm thrilled that Oxford County has finally switched over to their new simulcast system. Sounded like they went live with it on 7/29/25. They are still analog not digital, but they are now simulcast. For those who don't know how simulcast works, its basically a multi site system whereby the equipment voter automatically chooses ("votes") which site to use for receiving the mobile and portable field units based on the clearest signal, then that voted receive signal is transmitted out over all of the sites, in other words all sites are transmitting (repeating) the exact same voted signal at the exact same time. Special simulcast equipment and GPS based timing is needed to do that properly. Also all transmissions from Oxford RCC are also broadcast over every site simultaneously, all with perfectly synchronized audio an timing. This system is a HUGE improvement from what they previously had. I run the Sebago Lakes Region and Oxford County Fire and EMS feed, and it was always painful to have to listen to the weak staticky signal whenever Oxford County was using their northern site on Black mountain in Rumford. Now all that noise is gone and you can hear all calls across the county load and clear. Also there's no more of Oxford RCC paging and dispatching every call twice ! They used to do it once on one tower site and then again on another site. So Much better now! Give it a listen on my feed.
 

AA1PL

Member
Feed Provider
Joined
Aug 18, 2007
Messages
21
Location
Hope Valley, RI
It appears that Oxford County RCC has switched over to a simulcast system. I am hearing Med-Care Ambulance and Rumford fire a lot clearer. Black Mountain also sounded distant when listening to them in the past. I now noticed after every transmission from ORCC, it has a few second period open squelch. Not sure how to minimize or get rid of that. Do not know the particulars of how they are doing a analog simulcast system. Hope someone on this forum has more information how this system works.
Yes that open squelch noise the end of every transmission is known as squelch crash. The squelch crash is typically generated in the receiving radio (your scanner, portable or mobile radio for example) and is typically caused by the transmitted signal (the repeaters) not having "reverse burst" enabled at the end of their transmissions. Reverse burst very briefly changes the repeater's transmitted PL tone for about a quarter second or less at the every end of every transmission . Reverse burst on the transmitting end allows the receiving radio's squelch circuit to to cut off the transmission cleanly so people dont hear the squelch crash noise. Sounds like the Oxford County repeaters dont have reverse burst enabled, but I cant say for sure since I wasn't involved in this system. I've worked as a 2-way radio tech radio for over 35 years.
 
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